Arithmatic Mean Question Answers

Averages, Arithmetic Mean - CAT 2007 Preparation

Question 4 the day : October 21, 2003
The question for the day is a sample practice problem in Simple Average, Arithmetic Mean on change in the average with change in number of elements - an Arithmetic Topic and the problem provides an understanding of the different concepts related to Averages.

Question
The average age of a group of 12 students is 20 years. If 4 more students join the group, the average age increases by 1 year. The average age of the new students is

1. 24
2. 26
3. 26
4. 22

Correct Answer is 24 years. Correct Choice is (1)

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Explanatory Answer

Total age of 12 students = 12 * 20 = 240 and the total age of 16 students = 21*16 = 336.

Let the average age of 4 new students be x.

Therefore total age of the new students = 4x.

Hence the total age of 16 students = 240 + 4x = 336 => x = 24